Electrostatic powder coating apparatus

Abstract

Electrostatic powder coating apparatus having an outer filter belt from which excess powder is removed by an elongated pick-up tube which extends across the width of the belt. The ends of the filter belt, instead of being joined, are overlapped, such that the uppermost end of the belt faces the direction which is opposite to the travel direction of the belt, avoiding interference with the powder pick-up tube.

I claim as my invention: 
     
       1. An electrostatic powder coating installation, comprising: an enclosure having airborne powder therein,   a filter belt disposed in a loop,   said filter belt having first and second major surfaces, first and second ends and first and second lateral edges,   said filter belt being permeable to air but not to said airborne powder,   drive means for moving said looped filter belt through the enclosure in a predetermined direction,   means for moving air within said enclosure towards said filter belt, with the first major surface of said filter belt being an outer surface upon which powder may collect as the drive means moves said filter belt through said enclosure,   powder removal means disposed in close promixity to the first major surface of said filter belt, for removing powder from said filter belt,   said filter belt having a length in a direction between its first and second ends which exceeds the loop length,   means attaching the first and second lateral edges of said filter belt to said drive means while overlapping the first and second ends, said first and second ends of the filter belt being devoid of joining means, said first and second ends being overlapped such that the uppermost end of the loop is directly exposed to the powder as the filter belt is driven through said enclosure, with the overlapped first and second ends providing a powder seal, said uppermost end of the filter belt loop being oriented to face the direction opposite to said predetermined travel direction, to prevent interference between said uppermost belt end and the powder removal means.   
     
     
       2. The electrostatic powder coating apparatus of claim 1 wherein the drive means includes first and second spaced chains disposed in loops adjacent to the first and second lateral edges of the filter belt, and means linking the first and second lateral edges with said first and second chains, respectively. 
     
     
       3. The electrostatic powder coating apparatus of claim 1 wherein the drive means includes a wear belt disposed in a loop, with the filter belt being disposed about the looped wear belt, said wear belt having a permeability to air at least as great as the filter belt. 
     
     
       4. The electrostatic powder coating apparatus of claim 2 wherein the wear belt has first and second ends and first and second lateral edges, and a length between its ends which exceeds its loop length, with the ends of the wear belt being overlapped and oriented such that the uppermost end faces the predetermined travel direction. 
     
     
       5. The electrostatic powder coating apparatus of claim 3 wherein the overlapping ends of the filter belt are circumferentially spaced from the overlapped ends of the wear belt. 
     
     
       6. The electrostatic powder coating apparatus of claim 3 wherein the drive means includes first and second spaced chains disposed in loops adjacent the first and second lateral edges of the filter belt, and means linking the first and second lateral edges of said wear belt and of said filter belt, with said first and second chains, respectively.